Spreaders may be loaded with a variety of materials of different density, grain size and water content. Most commercial spreader material contains fines mixed with the lumps, pellets, granules or powder constituting the main weight of the material to be spread.
Fines cannot be thrown as far by the spinners as the heavier material and these tend to be deposited in a band across the rear of the spreader from wheel to wheel while the heavier material lands toward the maximum range of the spinner. Thus the fines present a problem. If the material is granulated by dampening with water, when thrown from the spinners it may shatter into fines against the spreader vehicle and undergo minimal spreading. Even if a guard is provided around the rear of the vehicle, fines tend to stick to the guard and build-up may occur.
Refinements in vehicle guidance and the metering of material have advanced to the stage where the performance of the spinners now lags and a patchy spread pattern is not acceptable. The spread path lies in a band to the left and right of the spinners up to 20 meters wide depending on the mass of the particles and spinner rpm. The spreading contractor aims for minimum band overlap. The material leaves the spinners from all four quadrants--and inevitably the material leaving the inner rear quadrant spreads to the rear. Material leaving the outer front quadrant strikes the vehicle's extremity.
The object of this invention is to deal differently with the material which strikes the spreader in the course of spreading.